What is Killing My Antique Rose?

Hello all, new here. :)
I have two beautiful and vigorous (until last month) Blanca de Coulbert rose bushes. I noticed branches dieing off very quickly. There doesn't appear to be fungus or spot. Just very quick die off.

A few days earlier a landscaper came and so I am thinking this is herbicide damage but wanted your opinion. In case it was, I went out and flooded the roots a few times but every day I have dead branches. It even seems that within 24hours, a healthy branch is dead. This has been occurring for 4 weeks now.

Any suggestions as to what this is and how I can save them would be appreciated. they are 4 years old.

i would find out what and if any herbicide was applied

Hi drobarr, thank you for your reply.
I did contact the lawn service and and asked him what happened and he told me it's not herbicide damage, that it is a fungus.This does not look like a fungus to me.

Look at the base of each stem that is dying. There may be an insect or other pest (vole, gopher) that is doing significant damage to the stem. Something that cuts off circulation way down on the stem can make the whole stem (above the damage) die back really fast in the summer heat. 24-48 hours.
Animals like voles will eat the bark or skin off the plant, leaving the harder interior wood.

Of course the gardener won't admit to applying herbicide- he would have to pay for your roses.

If its fungal it could be Phytophthora. It is odd the problem happened after the lawn service came. Though if it was some sort of herbicide the problem would tend to go away with time and likely affect th entire plant...not just a few branches and appear on new branches up to a month later. I cant think of any other disease with those symptoms. Rose stem borers symptomology is also different. Also bacterial diseases like fireblight tend to have a much darker black like foliage.

Try getting a systemic rose fertilizer/fungicide/insecticide and see if that helps. http://www.bayeradvanced.com/rose-flower-care/products/all-in-one-rose-flower-care

Thanks so much drobarr. I did a search on Phytophthora and it does look like that may be it. In fact, taking a look at the images on the web, it looks like I have this all over my garden, infecting vegetables and other plants.

We are organic gardeners and have a pollinator sanctuary on our land, so we won't be using the Bayer product as an ingredient in it has been known to cause pollinator deaths. But I will definitely hunt down other options to try to eradicate it.

If it's not this disease,(as I also find it odd it happened right after the landscaper was here) it would be herbicide I think. Thanks for narrowing it down for us.

This message was edited Sep 8, 2013 12:42 PM

Diana_K, I went outside this morning and did not see any evidence damage from chewing. But I thank you for that suggestion. This is like detective work.

For organic control there arent many options. Try to eradicate diseased tissue and burn or throw away...do not compost. Phytophthora is really bad this year. Serenade might prove helpful as well.